Apparatus for manufacturing electric power cables



Jan. l2, 1965 ITARU wATANABE ETAL 3,155,202

APPARATUS FOR MANUFACTURING ELECTRIC POWER CABLES Filed April 30, 1963 FEL/ff 'A' an F. nl' Q1 ATTORNEYS United States Patent C) 3,165,292 APPARATUS FR MANUFACTURNG ELEC'IRIC PSV/EP. CABLES Itaru Watanabe, Keiao Kushihashi, Seiji Tsuchiya, and Tetsuro Terada, all of Yokohama, .apan, assignors to The Furukawa Eiectric Company Limited, Tokyo, Japan, a corporation of Japan Filed Apr. 30, 1963, Ser. No. 276,782 4 Claims. (Ci. 207-4) The present invention relates to improvements in the apparatus for manufacturing power cables, more particularly oil-filled cables.

Oil-filled cables are filled with insulating oil of low viscosity -by means of oil passages. In manufacturing such cables there are two processes, one of which is that the cable core is sufficiently dried at first in an enclosed drying casing, then a sheath of lead or aluminum is applied, and the sheathed cable is then heated from outside to extract air and moisture from each end (this heating is called the secondary drying, while the drying before applying the sheath is called the primary drying, then insulating oil is filled in the sheath. According to this process, the cable core is exposed to open atmosphere while the sheath is applied` so that it needs the secondary drying. However if in this process the cable core was to be protected from the atmosphere, the secondary drying could be dispensed with.

The second process is to dry the cable core to high degree, impregnato it with refined and de-gassed insulating oil, and succeedingly apply thereto the sheath. According to this process, ditterent from a solid cable, it is necessary to carry out the process without contacting oil-impregnated cable core with external atmosphere by connecting the drying and oil impregnating casing with a press or an extruder of sheath by means of airtight tube.

The present invention relates to an apparatus for carrying out the tirst process without the secondary drying, or for carrying out the second process. The apparatus comprises an enclosed casing for drying the cable core and impregnating it lwith insulating oil, a press or an extruder for applying sheath to the cable core, a communication tube hermetically connecting said casing and .said press or extruder for passing the core therethrough, kand `a cable guide device for leading the core from the casing through the communication tube to the press or extruder without contacting the core with external atmosphere, wherein the cable guide device consists of a plate valve, tension wires, etc. Said plate valve is pressed on .the inner flange provided in the communication tube to hermetically seal the casing and the press or extruder. When the cable guide device is pulled through the press or extruder, the plate valve is deformed and can pass through the nipple holder and nipple in lthe press or extruder.

For a better understanding of the invention reference is made to the accompanying drawings, in which FGS. 1 and 2 are sectional side elevations of two embodiments of the apparatus of the invention for manu- 4facturing power cables;

' FIGS. 3 to 6 are partial sectional views of the essential parts of the apparatus of the invention illustrating several modiiications. I

Referring to the drawing, 1 represents an enclosed casing in which the cable core 2 is either dried or dried and impregnated with insulating oil. 3 represents a press or an extruder for extruding lead or aluminum to cover the cable core. In accordance With the invention, the casing 1 and the press or extruder 3 are connected with a communication tube 4 hermetically, and cable guide device 5 is provided in the tube to pull the cable core ICC from the casing 1 into the press 3 without contacting external air. In guiding cable core 2, which is either dried or dried and impregnated with insulating oil, to the press or extruder 3 without contacting external air, the construction of the cable guide device posses a problem and it is constructed as follows according to the invention.

FG. 3 shows an embodiment of the invention more clearly, wherein a plate valve 7 is secured to one end of a tag 6 by eye bolt 8 and -bolts 9, 9', etc. and also to one end of the cable core by means of a tension wire 16. The plate valve 7 is located at the tlanged portion 13 of the tubes 11 and lZto airtightly partition them off. In order to lead the cable core 2 into the press or extruder 3 by means of said cable device, the tension wire 16 connected to the tag 6 is pulled out through the nozzle of the press or extruder 3 as shown in FIG. l. The plate valve 7 is at first pressed on the iiange 11i at the left side of FIG. 3, and the casing 1 is evacuated. The plate packing 7 is pulled by the negative pressure to make tight contact with the flange liti', thereby tightly sealing the casing 1; thus the casing 1 is evacuated and dehydrated by suitable means and the cable core is dried thoroughly. Then insulating oil is tilled in the casing 1 by suitable means and the gradually pressurized. When the pressure in the casing 1 is raisul, the plate valve 7 is pressed to the right side to make contact with the opposite tiange 10, so that the tlowing out of insulating oil is prevented by partitioning ott a chamber 14 lin the tube 11 from a chamber 15 (refer to FIG. 3).

Next, the tension wire 16 as shown in FIG. l connected to the tag 6 is lead out through the press or extruder 3 where the sheath 3) is sealed at 17 securing the tubes 11 and 1S and a pressure regulating device 19 in position. The inside of the tube is evacuated by means of the pressure regulating device 19 and the moisture is thoroughly removed. Then the insulating oil is fed therein from a previously arranged oil tank (not shown) to make the oil pressure almost equal to that in the chamber 15 in- -side of the tube 12, thus the pressures on opposite sides of the plate valve 7 become almost equal to each other, so that the plate valve 7 is made free to communicate both chambers. Under such conditions, when the press or extruder 3 is operated to pull out the tension wire 16, the plate valve 7 is deformed, and pulled out together with the tag 6 through the tubes 11 and 18 and the press or extruder 3, so that the cable core 2 can Vbe covered with lead or aluminum sheath without contacting external air.

The shape of the plate valve is not necessarily limited to a plate. FIG. 4 illustrates another embodiment ot the cable guide device used in the invention, wherein the pla-te valve '7 is funnel-shaped. With such construction, the valve effect between plate valve 7 and flanges 10, 1li is further improved. It has an advantage that when the tag 6 is shifted to the side of the press or extruder 3, the plate valve 7 can be deformed more easily.

FiG. 5 illustrates further embodiment of the cable guide device wherein the plate valve 7, similar to that of FIG. 3, is rigidly connected to the tag 6 by eye bolt 8 and bolts 9, 9', etc., and also to one end of the cable core by means of a tension Wire 16', and the plate valve 7 is located between flanges 10 and 10 tightly fitted to either one of them according to the pressure difference, saine as in FIG. 3. In this case, grooves 20 and 20', annular and otherwise shaped, are provided in the tianges l@ and 10 respectively and are connected through pipes 23 and 23 to vacuum devices 22 and 22 respectively. With such construction and arrangement, when the chambers 14 and 15 inside the pipes'11 and 12 respectively are to be separated, the groove 20, for instance, is evacuated by the vacuum device 22 and the plate valve 7 is sucked by the negative aree-,soa

,.9 pressure to firmly contact with the liange lli, so that much more excellent packing effect can be obtained than in the case of FTG. 3.

FIG. 6 illustrates a modified form or" FIG. 5 wherein the vacuum devices 22 and 22' are dispensed with by connecting the kgrooves 24B and Ztl by means of pipes 24 and 24 respectively to the chambers ld and l5 directly. When the chamber M or l is evacuated, the groove 22 or Z2 can be evacuated at the same time, thereby assisting the more rigid Contact of plate valve 7 with the liange 1% or lh.

ln cable guide devicesas shown in FIGS. 3 to 6 the plate valve 7 is made to tightly contact with either side of the flange lli or lil. lf it is used under such condition that when one of the chambers i4 and l5 is always at a lower pressure than the other, either one of ythe flanges l@ and lll is suflicient.

Two or more such cable guide devices can be used also in series.

The plate valve used for the apparatus under the invention will produce more satisfactory results if its average thickness is 1/2 inch or under.

According to the apparatus of the invention, the cable core 2 can be pulled towards the ress or extruder 3 by means of a tension wire 16 by using a cable guide device having plate valve 7 and tag 6 as shown in FlG. l. Yet it can be more positively shifted by using a magnetic device as shown in FIG. 2, wherein the tube 18 is made of non-magnetic material such as brass pipe, and an iron core is connected to the tag 6 by the tension wire 16. The iron core 25 is connected via a rigid rod 26 with a plug 217. Tag 6 having plate valve 7 is connected to the end of cable core 2, and a solenoid 2% is provided outside cf the tube le at a position corresponding to the iron core 2.5'. v

When the above described device is used to shift 'the cable core Z to the press or extruder 3, the press or extruder is operated at lirst to extrude the sheath 3% and airtightly seal an end 31, then the tubes lll, 13 and the sheath 3l? are evacuated by the pressure regulating device llt), and afterwards solenoid 29 is energized and shifted towards the press or extruder 3 moving iron core 25 in the same direction; then the plug 27 can be inserted into the sheath Ell. The plug 27 inserted into the sheath 3i) is tightly `fixed to the latter and pulled out of the press or extruder 3. The cable core 2 connected to the plug 27 can be led into the press or extruder 3 to apply a sheath thereon without contacting external air. 'ln this case, the solenoid 29 is de-energized as soon as insertion Vof the plug 27 is completed.

ln the foregoing, the cable core is only dried, but when the cable core is dried and impregnated with insulating oil, theabove described operation may be carried out after the communication tube is evacuated and then iilled with insulating oil.

The solenoid can be energized under the lixed condition instead of shifting the solenoid to the side ot the press as explained with reference to FG. 2; if the solenoid Z9 is located nearer to the press or extruder 3 than the position of iron core 25 in FlG. 2 and is energized after the preparation is ready as above described, the iron core 25can be pulled towards the solenoid, thereby inserting the plug 27 into the sheath 30.

When the cable core is impregnated with insulating oil, the plug 27 in FlG. 2 is located in the nipple 32 instead of in the nipple holder 33. Only in this case, plug 257 is so made as to lit well into the nipple 32. The solenoid 29 is arranged on the outside of the iron core 25 which is held at that position by energizing the solenoid. Under description is made of the case where this condition the inside of tubes lll, i8 and sheath 30 is evacuated, then insulating oil is filled in the tubes 1l, 1S and nipple holder 33 to reach the back of the plug 27, the oil is subjected to pressure, the solenoid is cle-energized to release its holding force and the plug y27' is forced into the sheath 3@ by the oil pressure to pass the cable core through the press.

According to the device ofthe invention as above described, when the cable core is dried by means of a dryingapparatus or when it is dried and impregnated with insulating oil by means of drying and impregnating apparatus, the plate valve which is a part of the cable guide device is used to interruptthe'cable core from external atmosphere, and, thereafter when the sheath is applied by'means of a press, the tagconnected with the plate valve is further Vconnected with the tension wire, or alternatively an iron core having a plug connected via the rod to the tag, and the iron core can be pulled into the press by magnetic force worked via the non-magnetic tube by the solenoid, without contacting the cable core with external air.

This being the case, it is possible to manufacture with high eiiciencyfcables of excellent electrical properties.

What we claim is: Y

l. An apparatus for manufacturing power cables which comprises in combination, a casing for drying the cable core and |impregnating it withinsulating oil having an outlet opening therein, a press having a nipple and a nipple holder for applying metal sheath to the cable core, a communication tube between said casingV outlet opening and said press, hermetically connected to them to pass said core therethrough, spaced parallel anges between said casing outlet opening and said communication tube, a cable guide device for leading said core from said casing through said communication tube to said press without contacting s-aid core with external air, a vacuum pump connected to said communication tube, said cable guide device consisting oa plate'valve attached to seal the outlet opening of the casing and a tension wire connected to said plate valve, -said plate valve Vcontacting with the flanges of the casing outlet opening and said communication tube, said plate valve being so constructed as to deorm when pulled by means of the cable guide device passingthrough the communication tube and the nipple holder yand nipple in said press.

2. An apparatus for manufacturing power cables according to claim l, wherein the angesV at the jointing ends of said casing and said communication ytube are each provided with such a groove fas ensures tight contact of `the 'plate valve and the flanges through evacuation of it.

3. An apparatus for manufacturing power cables according to claim l, wherein said plate valve is funnel shaped.

4. An apparatus for manufacturing power cables according to claim 1, wherein a portion of said communication tube is made non-magnetic, said cable guide device comprises an iron core connected to a rod fixed to a plug, and a solenoid isprovided outside of said non-magnetic communication tube to shift the iron core to the press. Relierences Cited by the Examiner UNTED STATES PATENTS 2,097,501 V11/37 Reichelt -f 156-54 2,790,597 4/57 Turpin 137-525 2,960,109 11/,60 Wilson 137-525 3,013,912 12./61 Prrargggiaet a1. 156-51 Y 3,032,464 5/62 Grieve 156-51 MICHAEL V. BRINDISLPrz'mary Examiner. CHARLES W. LANHAM.Y Examiner., 

1. AN APPARATUS FOR MANUFACTURING POWER CABLES WHICH COMPRISES IN COMBINATION, A CASING FOR DRYING THE CABLE CORE AND IMPREGNATING IT WITH INSULATING OIL HAVING AN OUTLET OPENING THEREIN, A PRESS HAVING A NIPPLE AND A NIPPLE HOLDER FOR APPLYING METAL SHEATH TO THE CABLE CORE, A COMMUNICATION TUBE BETWEEN SAID CAUSING OUTLET OPENING AND SAID PRESS, HERMETICALLY CONNECTED TO THEM TO PASS AND CORE THERETHROUGH, SPACED PARALLEL FLANGES BETWEEN SAID CAUSING OUTLET OPENING AND SAID COMMUNICATION TUBE, A CABLE GUIDE DEVICE FOR LEADING SAID CORE FROM SAID CASING THROUGH SAID COMMUNICATION TUBE TO SAID PRESS WITHOUT CONTACTING SAID CORE WITH EXTERNAL AIR, A VACUUM PUMP CONNECTED TO SAID COMMUNICATION TUBE, SAID CABLE GUIDE DEVICE CONSISTING OF A PLATE VALVE ATTACHED TO SEAL THE OUTLET OPENING OF THE CASING AND A TENSION WIRE CONNECTED TO SAID PLATE VALVE, SAID PLATE VALVE CONTACTING WITH THE FLANGES OF THE CASING OUTLET OPENING AND SAID COMMUNICATION TUBE, SAID PLATE VALVE BEING SO CONSTRUCTED AS TO DEFORM WHEN PULLED BY MEANS OF THE CABLE GUIDE DEVICE PASSING THROUGH THE COMMUNICATION TUBE AND THE NIPPLE HOLDER AND NIPPLE IN SAID PRESS. 